By virtue of the progress in the Internet, information communication networks and the like, each of users can now easily access network information through a personal terminal employing a cellular phone or the like.
In such information communication, information is transmitted through digital signals. Therefore, each user can copy, e.g., music and video information transmitted via the aforementioned information communication network without degradation in the audio quality and picture quality. When any content data subject to copyright protection such as music data and image data is to be transmitted on the information communication network, copyrights of the copyright owner may be significantly infringed unless some appropriate measures to protect the copyrights are taken.
However, if copyright protection is given top priority so that distribution of content data over the disseminating digital information communication network is suppressed, the copyright owner who can essentially collect a predetermined copyright royalty for copies of a copyrighted work will also incur some disadvantages.
Instead of the distribution over the digital information communication network described above, distribution may be performed via record mediums storing digital data in a reproducible manner. In connection with the latter case, music data stored in CDs (Compact Disks) on the market can be freely copied in principle onto magneto-optical disks (e.g., MDs) as long as the duplication is only for the personal use. However, a personal user performing digital recording or the like indirectly pays predetermined amounts in prices of the digital recording device itself and the medium as guaranty moneys to a copyright owner.
Further, the user can copy the music data from a CD to an MD, but cannot copy it from an MD to another MD.
In view of the above, sufficient measures must be taken for the copyright protection when distributing the content data such as music data and image data taking the form of digital information to the public.
For example, a copyright owner or the like may wish to distribute music data in an appropriate distribution manner to an indefinite number of users, e.g., for sales promotion of new songs or tunes. However, if reproducible music data were simply distributed without reservations or restrictions over the digital information communication network, the copyright owner would be unable to collect charges from users without difficulty.
After a user receives the above music data, it is necessary to prevent unrestricted production of duplications in a reproducible form.
For another distribution system of music data, experiments are being conducted on operation of automatic dispensers or vending machines of music data to be located in railway stations, convenience stores and others. In this system, the music data is distributed to the automatic dispensers over a digital information communication network, and users can purchase the music content information from the automatic dispenser.
For selling the music data in the above automatic dispensers, the music data is recorded on a writable record medium such as a MD. Assuming that tens of seconds are required for recording one tune or song, a user who is purchasing about ten tunes at a time must wait several minutes for the purchase.